The present invention relates to an end face light-emitting-type LED (Light Emitting Diode), an end face light-emitting-type LED array, and methods of manufacturing them.
LED arrays have been used, for example, as light sources in electrophotographic printers. There is a type of LED array which is know by the name of end face light-emitting-type LED array.
Its structure and manufacturing method are disclosed, for example, in Japanese Patent Kokai Publication No. 125765/1990 (hereinafter, referred to as Publication 1). According to the page 3, left upper column of the Publication 1, the end face light-emitting-type LED arrays are formed by dicing a semiconductor wafer having a laminated structure which is composed of an N electrode, an N-type GaAs buffer layer, an N-type AlGaAs layer, a P-type AlGaAs layer and a P electrode.
In the conventional LED array, after forming the P-type region, the end face was formed by cutting both the P-type region and the N-type layer.
However, in the conventional end face light-emitting-type LED array, the end face was formed by cutting both the P-type regions and the N-type layer using a dicing machine and the like. In the LED array formed by this method, only the light emitted from P/N junctions below the P-type regions when viewed from the front of the end face is effectively extracted, so the light intensity emitted from each element was small.